Messung der körperlichen Fitness in der NAKO Gesundheitsstudie: Methoden, Qualitätssicherung und erste deskriptive Ergebnisse

Die körperliche Fitness ist das Maß für die individuelle Fähigkeit, körperlich aktiv zu sein. Ihre wesentlichen Komponenten sind die kardiorespiratorische Fitness (Cardiorespiratory Fitness, CRF), die Muskelkraft und die Beweglichkeit. Neben der körperlichen Aktivität ist die körperliche Fitness ein wesentlicher Prädiktor für Morbidität und Mortalität. Ziel der Arbeit sind die Beschreibung der Erhebungsmethoden körperlicher Fitness in der NAKO Gesundheitsstudie und die Darstellung erster deskriptiver Ergebnisse. In der NAKO-Basiserhebung wurden die maximale Handgreifkraft (Grip Strength, GS) und die CRF als Komponenten der körperlichen Fitness über ein Handdynamometer bzw. über einen Fahrradergometertest mit submaximaler Belastung erhoben. Daraus wurde die maximale Sauerstoffaufnahme (VO2max) zur Beurteilung der CRF abgeleitet. Die Ergebnisse von insgesamt 99.068 GS-Messungen und 3094 Messungen der CRF beruhen auf einem Datensatz zur Halbzeit der Basiserhebung der NAKO (Alter 20–73 Jahre, 47 % Männer). Männer zeigten im Vergleich zu Frauen höhere Werte der körperlichen Fitness (Männer: GS = 47,8 kg, VO2max = 36,4 ml·min−1 · kg−1; Frauen: GS = 29,9 kg, VO2max = 32,3 ml·min−1 · kg−1). Ungefähr ab dem 50. Lebensjahr konnte ein Rückgang der GS verzeichnet werden, wohingegen die CRF ab der Altersgruppe 20–29 Jahre bis zu den ≥60-Jährigen kontinuierlich abfiel. Die GS und die VO2max zeigten nach Korrektur für das Körpergewicht einen linear positiven Zusammenhang (Männer β = 0,21; Frauen β = 0,35). Die Analysen zeigten eine gute Übereinstimmung der Verteilung der körperlichen Fitness in der NAKO im Vergleich zu anderen bevölkerungsbasierten Studien. Zukünftige Auswertungen werden insbesondere die unabhängige Bedeutung der GS und CRF bei der Prädiktion von Morbidität und Mortalität beleuchten.Physical fitness is defined as an individual’s ability to be physically active. The main components are cardiorespiratory fitness (CRF), muscle strength, and flexibility. Regardless of physical activity level, physical fitness is an important determinant of morbidity and mortality. The aim of the current study was to describe the physical fitness assessment methodology in the German National Cohort (NAKO) and to present initial descriptive results in a subsample of the cohort. In the NAKO, hand grip strength (GS) and CRF as physical fitness components were assessed at baseline using a hand dynamometer and a submaximal bicycle ergometer test, respectively. Maximum oxygen uptake (VO2max) was estimated as a result of the bicycle ergometer test. The results of a total of 99,068 GS measurements and 3094 CRF measurements are based on a data set at halftime of the NAKO baseline survey (age 20–73 years, 47% men). Males showed higher values of physical fitness compared to women (males: GS = 47.8 kg, VO2max = 36.4 ml·min−1 · kg−1; females: GS = 29.9 kg, VO2max = 32.3 ml · min−1 · kg−1). GS declined from the age of 50 onwards, whereas VO2max levels decreased continuously between the age groups of 20–29 and ≥60 years. GS and VO2max showed a linear positive association after adjustment for body weight (males β = 0.21; females β = 0.35). These results indicate that the physical fitness measured in the NAKO are comparable to other population-based studies. Future analyses in this study will focus on examining the independent relations of GS and CRF with risk of morbidity and mortality

A systematic approach to reliably characterize soils based on Bevameter testing

Although there exists a lot of information about soil parameter identification in literature, currently there is no algorithm both making use of state of the art identification methodologies and incorporating statistical analysis. In this paper a state of the art soil parameter identification method is presented including the calculation of their standard deviations and a proper weighting of the objective function. With this algorithm and a Bevameter with advanced sensor and actuator technology a test campaign is started to find a reliable soil preparation which is applicable to a large planetary rover performance testbed. Furthermore the preparation method has to be valid and stable for various types of granular soils, typically used for planetary rover testing in space robotics, since the result of pre-tests show that the soil parameters are highly depending on the preparation. Besides to the preparation soil parameters are influenced by different Bevameter test setup variables, too. Thus the effect of the penetration velocity as well as the penetration tool geometry for pressure-sinkage tests on soil parameters is investigated. For shear tests the influence of the dimension of the shear ring is also analysed as the variation of the grouser height, the number of the grouser and the increase of the rotational shear velocity. The results of the extensive test campaign are evaluated by the proposed identification algorithms

Konzeption und Entwicklung einer Testanlage für planetare Rover zur Messung von Bodenparametern

Im Rahmen dieser Diplomarbeit wird ein Bodenparametertestgerät methodisch konstruiert. Es beruht auf dem Grundaufbau eines Bevameters. Hauptzweck des Testaufbaus ist es, für die rechnergestützte Simulation möglichst genaue Werte von Bodenparametern zu liefern. Die Bestimmung von charakteristischen Bodenparametern steht dabei im Kontext der Validierung von mathematischen Simulationsmodellen. Dabei werden interativ Einzelrad- und Gesamtfahrzeugmodelle korreliert und die charakeristischen Bodenparameter überprüft. Im ersten Kapitel der Arbeit werden die Aufgabenstellung und die Probleme der bisherigen Bodenmessgeräte gezeigt. Es wird außerdem kurz auf die Umgebungsbedingungen auf dem Mars insbesondere den Boden eingegangen. Die Grundlagen der Bodenmechanik werden im zweiten Kapitel beschrieben. Es wird weiter auf das mechanische Verhalten zwischen Rad und Boden, der sogenannten Terramechanik, eingegangen. Außerdem werden die heute üblichen Messverfahren zur Erlangung der verschiedenen Bodenparameter beschrieben und erklärt. Abschließend wird beschrieben, welche Schritte bei der Konstruktion des Bevameters nötig sind. Der erste Schritt ist dabei eine ausführliche Problembeschreibung, um die Anforderungen an den Messaufbau zu klären. Dazu werden die Anforderungen an die Konstruktion in einer Anforderungsliste erfasst und eine Funktionsstruktur aufgestellt. Eine Untersuchung der Produkte verschiedener Firmen, sowie eine Recherche in Literaturen und Internet zeigt, dass keine vorhandene Lösung den Anforderungen gerecht wird. Nach Abschluss der Problembeschreibung kann mit der Lösungssuche für das Bevameter begonnen werden. Mit Hilfe von Wirkprinzipien werden Lösungen für Teilfunktionen gesucht. Diese Wirkprinzipien werden anschließend in den sogenannten morphologischen Kasten zusammengetragen. Aus diesem Kasten werden Prinziplösungen erstellt und anschließend bewertet. Daraus entsteht ein Konzeptaufbau für das neue Bevameter. Im nächsten Schritt werden Entscheidungen getroffen, die die Fertigung und Entwicklungskosten eingrenzen. Außerdem werden Antriebskonzepte entwickelt und ausgewählt. Anschließend werden die Schritte Konstruktion und Bestellung der Bauteile des Bevameters beschrieben. Am Ende werden der Aufbau und die erste Versuchsdurchführung kurz beschrieben

A novel Terramechanics testbed setup for planetary Rover wheel-soil Interaction

For planetary rovers, demonstration of the overall mobility performance on soft soil is a demand to guarantee for mission success. Since several years, DLR’s Institute of Robotics and Mechatronics is strongly engaged in planetary mobile system developments. For the very important wheel-soil interaction a 3D-MBS tool for modeling and simulation of the overall terramechanics behavior, making use of Bekker’s well-known terramechnical equations, has been developed. Currently, major applications are followed within ESA’s Exomars mission. For the purpose of verification and validation of the 3D-MBS tool intensive hand in hand rover testing in a lab environment is necessary. Therefore, a new facility for planetary locomotion systems including a large testbed and a novel, high-precision bevameter to characterize the soil on which the tests are to be carried out is presented. For precise rover pose estimation inside the testbed a high-level position tracking system is used, and for proper soil surface determination on an in-house developed digital elevation mapping system is relied on. For the Bekker parameter determination, a portable and lightweight bevameter equipped with a state-of-the-art sensor technology is designed. Different design concepts are analysed open minded without any orientation on existing bevameter designs. This leads to a tripod design with electromechanical actuators and sensors integrated in a real-time computing environment to develop own control algorithms. Besides soil testing and soil preparation influence detection, the bevameter is mainly used for identifying soil parameters of the testbed. Finally, for correlation purposes, these parameters are taken as inputs to the 3D-MBS tool for simulating the drive manoeuvres performed inside the testbed. Results obtained from bevameter testing are presented together with the testbed setup design

A systematic approach to reliably characterize soils based on Bevameter testing

Although a lot of information about soil parameter identification exists in literature, there is currently no algorithm who makes use both of state of the art identification methodologies and incorporating statistical analysis. In this paper a state of the art soil parameter identification method is presented including the calculation of its standard deviations and a proper weighting of the objective function. With this algorithm and a Bevameter with advanced sensor and actuator technology a test campaign is started to find a reliable soil prep- aration, which is applicable to a large planetary rover performance testbed. Furthermore, the preparation method has to be valid and stable for various types of dry, granular and frictional soils, typically used for planetary rover testing in space robotics, since the result of pre-tests show that the soil parameters are highly depending on the preparation. Besides preparation, the soil parameters are also influ- enced by different Bevameter test setup variables. Thus, the effect of the penetration velocity as well as the penetration tool geometry for pressure–sinkage tests on soil parameters is investigated. For shear tests the influence of the dimension of the shear ring is analysed as well as the variation of the grouser height, the number of the grousers and the increase of the rotational shear velocity. The results of the extensive test campaign are evaluated by the proposed identification algorithms

Mobility Challenges and Possible Solutions for Low-gravity Planetary Body Exploration

Currently, a number of missions in the field of small bodies exploration, e.g. to asteroids, are ongoing or planned (amongst others Hayabusa 2 by JAXA or the follow-on of Marco Polo by ESA). Several of these missions foresee a lander package for in -situ science (e.g. proposed MASCOT for Hayabusa 2). To enhance functional safety as well as science possibilities, the provision of mobility on the target body is widely appreciated. However, due to the very low gravity influence, possible solutions are different fro m present ones for larger gravity planets and moons such as Mars and the Earth’s Moon. The paper gives an overview about simulation and testing activities which lead to promising mobility concepts for micro-gravity environment

Development of a Mobility Drive Unit for Low Gravity Planetary Body Exploration

The 10 kg asteroid lander package MASCOT (mobile asteroid surface scout), developed by DLR, is a contribution to the JAXA Hayabusa-II mission, intended to be launched in 2014. MASCOT will provide in-situ surface science at several sites on the C-type asteroid 1999 JU3. An innovative hopping mechanism, developed at the Robotics and Mechatronics Center (RMC) in Oberpfaffenhofen, allows the lander to upright to nominal position for measurements as well as to relocate by hopping. The mechanism concept considers the uncertain and harsh environment conditions on the asteroid surface by using the impulse of an eccentric mass with all rotating parts completely inside the MASCOT structure. The paper gives an overview of the major development activities which lead to a new promising powerful and scalable drive system for low gravity planetary body exploration

Rapid modeling of high resolution moon-like terrain models for testing of optical localization methods

This paper presents an intuitive approach for the rapid generation of arbitrary high resolution Digital Elevation Models (DEM) of moon-like surfaces, with minimal required extra expertise. It combines manual terrain shaping in a soil bin with automatic generation of 3 mm resolution DEMs. The generated DEMs are upscaled to 0.3 m resolution and integrated into lower-resolution DEMs of the lunar surface. The resulting model is used in the DLR project ATON (Autonomous Terrain based Optical Navigation) to realistically simulate optical sensors deployed on a lunar lander, enabling simulation of a complete landing trajectory until touch down. Results for five different landing site DEMs are provided to demonstrate the flexibility in modeling

EXOMARS PHASE B2 BREADBOARD LOCOMOTION SUB-SYSTEM TEST CAMPAIGN

As part of the ExoMars mission the European Space Agency (ESA) plans to deploy a rover on the surface of Mars researching its exobiology and geology. The focus of this paper is the extensive testing performed in order to guarantee the rover mobility later on Mars. The test campaign, a joint collaboration between DLR and RUAG, assess and analyses the loads on the ExoMars Locomotion Sub-System (LSS) due to motion. The tests were carried out using functionally representative models of the envisaged ExoMars rover having the same kinematics. The paper presents the results of the test campaign carried out with the ExoMars LSS BB2 as well as the lessons learned